Okay, we have a musty smell coming from our a/c unit. From what I've read, it could be water collecting in the drain pan or the growth in condensate line. I did the easy thing first and checked the condensate line. No sign of a blockage. I added a cup of bleach followed by 2 cups of water. I was hoping this would help wth the smell. It hasn't. The other thing I was told to check was the drain pan. My question is how do I access it. I've attached a pic of my unit. Yes, the filter size is too big. I can't seem to find the right size at any local store, so I decided to put a bigger one rather than a smaller one. Anyway, back to the point.... The furnace is on top, the air handler in the middle, and blower on the bottom. I see some screws for the panel for the air handler, but can I remove it due to the fact that the refrigrant lines and condensate lines are attached? Or do I remove the furnace panel and look down? Even if I do that, will I be able to see the drain pain. I removed the filter and looked up. I could see the coils, but that was about it. I tried to see if I could find a manual or something for this particular air handler, but nothing came up. Its 10+ years old. Or is this better left to a professional.